Question

23. A student uses a compressed spring of force constant 22 N/m to shoot a 7.5 x 10 power of -3 kg eraser across a desk. The magnitude of the force of friction on the eraser is
4.2 x 10 power of -2 N. How far along the horizontal desk will the eraser slide if the spring is initially compressed 3.5 cm? Use the law of conservation of energy.

Answer 1

We can calculate the potential energy stored in spring by equation \[1/2 k x^{2}\] where k is force constant and x is the compression. You will get 134.75 J energy. If the whole amount of energy is transfered to eraser then we can use energy conservation as
the work done in traveling the distance y on a horizontal desk = Initial energy of eraser
If we take constant friction force acting on an eraser then
\[work done = force \times displacement\]
and this equal to energy of eraser 135.75 J
by solving this we get the distance travel by eraser is 3232.14 meter